Volume shrinkage of curable compositions during the curing process is known since a long time. Especially, in the dental area, this can cause problems as e.g. a gap might be formed between the cured composition and the wall of the tooth cavity. This might lead to an infection of the remaining tooth structure. Various attempts were undertaken to address this problem.
US 2009/0036565 relates to dental composites based on (meth)acrylates, exhibiting a proportion of TCD (i.e. tricyclo[5.2.1.02,6]decane-3/4,8/9-diyl) derived monomers, wherein the quotient of flexural strength/shrinkage tension is at least 35.
US 2008/0167399 relates to dental composites comprising a crosslinking agent formed from acrylates and a certain TCD urethane structure.
U.S. Pat. No. 7,601,767 B2 relates to a composite material containing i.a. a monomer component comprising a mixture of Bis-GMA or TCD-di-HEMA or TCD-DiHEA, UDMA and TEDMA.
U.S. Pat. No. 4,744,827 relates to certain (meth)acrylate acid derivatives of tricyclodecanes comprising a X—Y—O—CO—C(R5)=CH2 unit with X being a divalent bridge member from the group —O—CO—NH— and —N(R6)-CO—NH— and Y denoting a certain divalent bridge member.
U.S. Pat. No. 4,744,828 describes (meth)acrylic acid derivatives of tricyclodecanes which may comprise one or two units having the formula —X—Y—CO—CR5-CH═CH2, with X being a divalent bridge comprising the group —NH—CO—O— or NH—CO—NR6- and Y being a linear or branched hydrocarbon chain which has 2 to 10 carbon atoms.
However, there is still room for improvement especially with regard to the requirements to be fulfilled with respect to modern dental materials.
Thus, there is still a need for an improved dental composition, which can be used inter alia as a restorative or temporary or long term crown and bridge material.